安装docker的方法众多，这里记录下自己习惯使用的方式。
主要参考阿里镜像站。以centos系统为例，步骤如下：
1、安装必要的系统工具
# yum install -y yum-utils device-mapper-persistent-data lvm2
...
Dependency Updated:
device-mapper.x86_64 7:1.02.170-6.el7_9.5 device-mapper-event.x86_64 7:1.02.170-6.el7_9.5
device-mapper-event-libs.x86_64 7:1.02.170-6.el7_9.5 device-mapper-libs.x86_64 7:1.02.170-6.el7_9.5
lvm2-libs.x86_64 7:2.02.187-6.el7_9.5 lvm2-python-libs.x86_64 7:2.02.187-6.el7_9.5
Complete!
2、添加yum源码
# yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
Loaded plugins: fastestmirror, langpacks
adding repo from: http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
grabbing file http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo to /etc/yum.repos.d/docker-ce.repo
repo saved to /etc/yum.repos.d/docker-ce.repo
3、查看安装版本
# yum list docker-ce docker-ce-cli containerd.io --showduplicates |sort -r
* updates: mirrors.bfsu.edu.cn
Loading mirror speeds from cached hostfile
Loaded plugins: fastestmirror, langpacks
Installed Packages
* extras: mirrors.bfsu.edu.cn
...
docker-ce.x86_64 3:19.03.8-3.el7 docker-ce-stable
...
docker-ce-cli.x86_64 1:19.03.8-3.el7 docker-ce-stable
...
containerd.io.x86_64 1.4.6-3.1.el7 docker-ce-stable
...
* base: mirrors.ustc.edu.cn
Available Packages
4、安装（docker-ce-19.03.8、docker-ce-cli-19.03.8、containerd.io-1.4.6）
# yum install -y docker-ce-19.03.8 docker-ce-cli-19.03.8 containerd.io-1.4.6
...
Downloading packages:
(1/3): docker-ce-19.03.8-3.el7.x86_64.rpm | 25 MB 00:00:03
(2/3): docker-ce-cli-19.03.8-3.el7.x86_64.rpm | 40 MB 00:00:04
(3/3): containerd.io-1.4.6-3.1.el7.x86_64.rpm | 34 MB 00:00:09
----------------------------------------------------------------------------------------------------------
Total 9.8 MB/s | 98 MB 00:00:09
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : 1:docker-ce-cli-19.03.8-3.el7.x86_64 1/3
Installing : containerd.io-1.4.6-3.1.el7.x86_64 2/3
Installing : 3:docker-ce-19.03.8-3.el7.x86_64 3/3
Verifying : containerd.io-1.4.6-3.1.el7.x86_64 1/3
Verifying : 1:docker-ce-cli-19.03.8-3.el7.x86_64 2/3
Verifying : 3:docker-ce-19.03.8-3.el7.x86_64 3/3
Installed:
containerd.io.x86_64 0:1.4.6-3.1.el7 docker-ce.x86_64 3:19.03.8-3.el7
docker-ce-cli.x86_64 1:19.03.8-3.el7
Complete!
5、设置docker为systemd单元并运行
# mkdir -p /etc/systemd/system/docker.service.d
# systemctl daemon-reload
# systemctl enable docker
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
# systemctl start docker
6、简单的使用
# docker search busybox
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
busybox Busybox base image. 2355 [OK]
progrium/busybox 70 [OK]
radial/busyboxplus Full-chain, Internet enabled, busybox made f… 43 [OK]
...
# docker pull busybox
sing default tag: latest
latest: Pulling from library/busybox
Digest: sha256:f7ca5a32c10d51aeda3b4d01c61c6061f497893d7f6628b92f822f7117182a57
Status: Image is up to date for busybox:latest
docker.io/library/busybox:latest
# docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
busybox latest 16ea53ea7c65 2 weeks ago 1.24MB
